Existing Customer Details update using FBDI-19 Sheets

How to Update the Following Existing Customers Fields Using FBDI-19 Template.

Account Level:

Communication
-Account Contacts
-Contact Points
-Account contact Responsibilities

Profile History

Site Level:

Site Details
-Address Purposes

Communication
-Account Site Contacts
-Contact Points
-Account Contact Responsibilities

Profile History (Create)

Which Reference number Should I give while filling the Import Customer FBDI-19 template

Party:

Party Original System-(New or Existing value, In what format)
Party Original System Reference-(New or Existing value, In what format)
Party Site Original System-(New or Existing value, In what format)
Party Site Original System Reference-(New or Existing value, In what format)

Account: